Servant keeps donkey in corridor (7)
I believe the answer is:
passage
'corridor' is the definition.
(thesaurus)
'servant keeps donkey' is the wordplay.
'servant' becomes 'page' (I've seen this before).
'keeps' means one lot of letters goes inside another.
'donkey' becomes 'ass' (I've seen this before).
'page' placed around 'ass' is 'PASSAGE'.
'in' is the link.
(Other definitions for passage that I've seen before include "Excerpt" , "Book extract; transit" , "street" , "Way through; part of text" , "Piece of writing" .)